If at all possible, I ALWAYS recommend taking a migrate export and import it into a lab environment(VM, test server, etc) and complete the upgrade there first, that way you can go through the entire process and get an idea of what types of issues(if any) you'll more than likely face during the actual upgrade process! One last thing, remember to always take snapshots/backups/migrate exports on a regular basis as best practice recommends!

One of our guidelines at Check Point is to never touch a user's policy structure during upgrades, even if we think it could be optimized. This is because our customers' trust on upgrades and on our management servers is important. So after upgrading to R80.10, all your rules, objects and their enforcement will remain the same, only with nicer colors and better performance.

That being said, things that could change are:

1. Deprecated applications - will remain in the policy but introduce install policy warnings (in R7x these applications were also deprecated)

2. Incorrect database values, such as letters inside a service port number, will fail the pre-upgrade verification process and give you a chance to fix it prior to upgrade.

If you would like to have your policy optimized prior to upgrade, you could use SmartOptimize as described in the video above. Without SmartOptimize your policy will remain exactly the same after the upgrade.